1. Field of the Invention
The present invention relates generally to tubular actuators, such as paraffin wax and electroactive polymer roll actuators, that define a stroke and shape fixity; and more particularly to a tubular actuator that utilizes active material activation to produce or modify the stroke, fixity, and/or retain the achieved configuration.
2. Discussion of the Prior Art
Tubular actuators, such as paraffin wax, pneumatic flexible tube (i.e., muscle), and electroactive polymer roll actuators, have been developed and used to actuate systems. These actuators present a shape fixity (i.e., resistance to change in shape) and define a stroke typically along the longitudinal axis, wherein the stroke is characterized by a shift in operable dimension (“stroke length”), the force produced thereby, and the period required to effect the shift (“stroke period”). These actuators present various concerns in the art. For example, it is appreciated that the constant shape fixity and stroke offered thereby prevent one-size-fits-all solutions. Moreover, conventional tubular actuators typically present tradeoffs, e.g., between stroke force and energy consumption, or stroke length and stroke period.